1. Field of the Invention
The present invention relates to an erbium-doped fiber amplifier (EDFA) for reducing transient phenomena of an optical signal-to-nose ratio (SNR) and a bit error rate (BER) in a dynamic wavelength division multiplexing (WDM) system and an amplifying method thereof.
2. Description of the Related Art
WDM systems have been evolved into intelligent dynamic WDM systems attributed to efficiency, flexibility, and reliability. In a case where obstacles are put in the way of arbitrary paths of dynamic WDM systems into which optical add drop multiplexer (OADM) and optical cross connect (OXC) are integrated, paths of channels are changed to re-allocate channels or to insert new channels. Thus, the number of input channels and a total input power of an EDFA vary depending on states of nodes and paths.
A sudden variation of the number of input channels affects a gain of the EDFA and thus affects powers, OSNRs, and BERs of remaining channels. As a result, the performance of the EDFA may be deteriorated. To solve this problem, there is suggested a technique for adjusting the currents of pump LDs depending on the input power of an EDFA to keep up a gain. However, the technique cannot entirely remove transient phenomena of the OSNR and the BER.